Converting Propranolol 10mg TID to Once-Daily Dosing
Switch to propranolol long-acting (LA) 80mg once daily, which provides equivalent total daily dosing (30mg to 80mg) with sustained beta-blockade throughout 24 hours.
Recommended Conversion Strategy
The optimal approach is to convert propranolol immediate-release 10mg three times daily (30mg total daily) to propranolol LA 80mg once daily. 1
Rationale for 80mg LA Dosing
- The American College of Cardiology/American Heart Association guidelines recommend propranolol LA at 80-160mg once daily for hypertension management 1
- While the current total daily dose is only 30mg, propranolol LA has 30-50% lower bioavailability compared to conventional formulations, requiring dose adjustment upward 2
- Propranolol LA 80mg once daily represents the minimum effective dose in the guideline-recommended range and accounts for the reduced bioavailability of the sustained-release formulation 1, 2
- Studies demonstrate that propranolol LA 160mg once daily provides equivalent beta-blockade to conventional propranolol 80mg twice daily, suggesting approximately 2:1 conversion is appropriate 3, 4
Pharmacokinetic Considerations
- Propranolol LA has a prolonged terminal half-life of 8-11 hours compared to conventional formulations, allowing once-daily dosing 2
- Peak concentrations with LA formulations are significantly lower but occur later (approximately 10 hours post-dose versus 2 hours with immediate-release) 3
- Trough plasma levels at 24 hours are significantly higher with LA formulations, providing sustained beta-blockade throughout the dosing interval 3
- The LA formulation maintains clinically significant inhibition of exercise-induced tachycardia throughout a 24-hour period 2, 3
Implementation Protocol
Conversion Steps
- Discontinue propranolol IR 10mg TID and initiate propranolol LA 80mg once daily the following morning 1
- Administer the LA formulation at the same time each day, preferably in the morning 3
- No tapering of the immediate-release formulation is required when switching between propranolol formulations at equivalent or higher total daily doses 1
Monitoring Parameters
- Measure blood pressure and heart rate before conversion and within 1-2 weeks after switching 1
- Assess for adequate beta-blockade by checking resting heart rate and blood pressure response 3
- Monitor for signs of inadequate control (breakthrough hypertension, tachycardia) or excessive beta-blockade (bradycardia, hypotension) 1
Important Clinical Considerations
Dose Titration if Needed
- If 80mg LA once daily provides inadequate control, increase to 160mg once daily after 1-2 weeks 1
- The maximum recommended dose is 160mg once daily for most indications 1
- Elderly patients may require lower doses due to altered pharmacokinetics, though studies show good tolerability of standard dosing 5
Critical Safety Warning
- Never abruptly discontinue propranolol, as this can cause severe exacerbation of angina, myocardial infarction, and ventricular arrhythmias 1, 6
- This warning applies to all beta-blockers including both immediate-release and long-acting formulations 1, 6
- If discontinuation is necessary in the future, taper by reducing dose by 25-50% every 1-2 weeks 6
Contraindications to Verify
- Confirm absence of marked first-degree AV block (PR >0.24 seconds), second or third-degree heart block without pacemaker, cardiogenic shock, or decompensated heart failure 1
- Avoid in patients with severe reactive airway disease; propranolol is non-selective and blocks both beta-1 and beta-2 receptors 1, 6
- Use caution in patients with severe bilateral renal artery stenosis 1